Drier



D. DALIN March 24, 1936,

DRIER Filed Dec. 1o 1954 s sheets-Sheet 1 All] lEnnN.

, RRSP.

D. DALIN March 24, 1936.4

DRIER Filed Dec. l0, 1954 3 Sheets-Sheet 2 Mrch 24, 1936.

D. DALIN 3 Sheets-Sheet 3 eenetef-2t1e PATENTOFFICE l Dama `David Dalin,Milwaukee,.Wis. Applicants December 1o, '1934, serial No. 'isaiasi 12claimt. totem-s2) This invention Arelates to improvements in ,driers andrefers more particularly to` vacuum driers suitab'e for drying' grain,malt, vegetables and other similar materials.

l'Ihe typepf drier to which this invention is particularlyapplicable, inits general aspects' comprises a container for the material to be dried,`usually in the form `of a cylinder or' drum mounted for rotation oroscillation. Suitable means are provided for maintaining a high vacuumwithin the container so as to draw oi the gases from the material beingdried, and in general promote the drying process.

To eiect the drying, `it is necessary to supply heat to the drierand-heretofore thisohas been done mostgeneralLv by injecting steam intoa radiator structure or heat exchanger disposed within the container andwith which the material being dried contacted Vas the container wasrevolved or oscillated. y

rlhe radiator structure in its simplest form consisted of tubesextending substantially throughout the length of the drum andcommunieating with a header to which the steam supply was connected.

This past construction made no provision for circulation of thel heatingmedium. The steaml or other heating medium` used was injected into theradiator structure, but as the tubes comprising the radiator or heatexchange unit were dead ended, each tube had a dead air space in whichthe air did not mix with the steam, and as a consequence, muchvaluableheating surface was lost.

Attempts were made to overcome this deficiency A of past'drierconstructions by the'provision of pet cocks to relieve the trapped airfrom the tubeabut obviously this was an expensive requires ment and atbest was but a makeshift arrangement. The constant attention which itrequired defeated its pllI'POSe. i g

With this objection to past driers in mind, it is an object of thisinvention to improve the construction oi driers of this nature so as toinsure circulation of the heating medium and entirely obviate deadair-spaces or uneven heating of the material being dried.

More specifically it is an objectof this invenn tion to provide adrierconstruction Wherein the heating medium enters the drier at one end andis directly conducted to a bulkhead located at the opposite endthroughwhich theeheating medium is distributed to the various tubes or passagesof the heat exchanger to be conducted through the body 'ot the dryingmaterial and exhausted from the same end o f the apparatus at which itenters. s.

Another object of this invention is to promote the circulation of aheating medium through the heat exchanger by maintaining a suction on`the 6. discharge of the heat exchanger.

Another object of this invention is to provide novel means forwithdrawing the condensate of the heating medium from the apparatus.

Another object of this invention is to provide lll a novel shelfarrangement within the container on ,which the materialheing dried issupported and tumbled or turned as the unit revolves or oscllates backand forth.v

A further object of this invention is to utilize 15. the tubes orindividual elements of the heatexchanger or radiator to provide shelveson which the drying material rests.

Still another object of this invention is to so dispose the individualelements comprising the 20 shelves that while the material being driedis in a moist condition as at the start of the drying rocess, thematerial will slide back and forth across the shelves and be tumbled inits movement and after the drying process has progressed sum- 2liciently, .the material will drop through the shelves to avoiddamage tothe material which might result from causing it to slide or fall thejfull width of the container drum. y

With the above and other objects in view which' 30y will appear as thedescription proceeds, this .in-1 vention resides in the novelconstruction, coin-I bination and arrangement ofparts substantially ashereinafter described 'and more particularly defined by the appendedclaims. it being under- 35 stood that such changes in thepreciseembodiment of the hereindisclosed invention may be made as comewithin the lscope ottlieiclaims.

The accompanying drawings illustrate' -one complete example of thephysical embodiment oi wf the invention constructed according to thebest mode so far devised for the practical application oi the principlesthereof, and in which:

Figure 1 is a view in side elevation with parts broken away and insection of a drying unit'em- 45 bodying this invention;

Figure 2 is a cross section view taken through Figure 1 on the plane 'ofthe line 2 2; l

Figure 3 is a view similar to Figure 2 but showing the drum turned toanother position; -50

Figure 4 is a longitudinal section view through a portion of theapparatus taken on the plane of thedine iofy Figure 1;

Figure 5 is a cross section view taken through l on the plane of theline iii-E;

'manganeumedcetmseeuonview taklenmntheplane of the line C-Cofl'igure anA Flgure'lisanenlarged section view illustrating l a detail oi the drumconstruction.

Referring now more particularly to the accompanying drawings in whichlike numerals indicate like .parts throughout the several views, thenumeral 5 represents vgenerally the drum-like container of the dryingapparatus which is revolubly mounted in any suitable manner, as byrollers 3 tracking on rings 1 encircling the drum as shown.

Oneoiftherings1 hasaring gear tattached to itdwith which a drivingpinion 9 meshes to oscillate the entire structure through apredetermined number of degrees. The specinc manv ner in which thepinion 8 is driven and its direction of rotation is changed forms nopart of 20 this invention, and fis. therefore, not shown. A

The drum 5 comprises an outer casing Il and an inner concentric shell Ilwith a space I2 therebetween through which the heating medium circulatesas will be hereinafter more fully described.

'I'he inner shell II is shorter than the outer casingand is closed atone end by a header plate I3 spaced i'rom the adjacent end I4 of thecasing.

and at itsother end by a .fhollow bulkhead I5 3 likewise spaced from theadjacent end I8 oi.' the casing.

'Ihe proper spacing betweenV the shell and casingismaintained bytherings1 which, as best shown in Figure 7, extend into the casing and 85 havethe drum reaped ends u and le of the casing as well as its medialcylindrical body portion welded thereto. The adjacent peripheral prtlonso! the inner shell are also welded to the rings. c

The ring 1 adjacent the header plate I3 has a plurality of openings I1which communicate the Acylindrical space I2 encircling the shell II with/the compartment I8 provided by the inside oi' the cuppedend I4.

At the opposite end. oi' the shell, the cylindrical space I2is'communicated with the interior of the hollow bulkhead I5 through aplurality of openings I9 in the cylindrical wall of the shell. Toaccommodate -this latter communication between 50 the cylindrical spaceI2 and the interior of the hollow bulkhead, the inner wall 2l of thehollow bulkhead has its peripheral portion 2I directedinwardly as shown.The outer wall 22 oi' the hollow bulkhead I5 has its periphery tightlyiixed 55 to the adjacent end of the shell II.

The compartment I8 is thus communicated Vwith the interior of the hollowbulkhead I5 through the cylindrical space I2 encircling the shell.Further communication between these chambers or spaces is aiIorded by aplurality of tubes 23 in the nature of boiler tubes havi g one end iixedin holes in the header plate`^ 3 and their opposite ends fixed in holesin the inner 65 wall 20er the hollow bulkhead. These tubes 23,

together with the space I2, provide the heat exchanger or radiator forheating the material Within the shell Il. For charging and dischargingthe drier, an

70 opening 24 is provided. The opening 24 is defined by a short cylinderpassing through and welded to the peripheries of holes in the innershell and the outer casing. A removable cover 25 normally closes the'opening.v If desired, a separate dis- 75 charge opening may be provided,but ordinarily the one opening 24 is suiilcient both for charging anddischarging the drier.

The heating medium most generally used is steam, and in the presentembodiment, it circulates continuously through the heat exchanger orradiator structure so as to insure uniform heat distribution.

To conduct the steam into the heat exchanger or radiator structure, asteam line 21 having'a cohtrolllng valve 28 passes through thecompartment I8 to be connected to a supply tube 28 at the header plateI3. The connection 30 between the steam line 21 and the tube 29 isillustrated in detail in Figure 6. As here shown, the tube 29 is rigidlysecured to the header plate I3 and the adjacent end of the steam line 21has a freely rotatable, but fluid tight connection with the header platein axial alignment with the tube 29. I

Any suitable construction may be used at this point and in the presentinstance, a flange 3| is welded to the outer face of the header plate torotatably receive the adjacent end of the steam line with a packing ring32 between the steam line and the iiange to provide a uid tight sealtherebetween.

' The tube 29 divides into two branches directly inwardly of the headerplatekas best shown in Figure 4 and lthe ends of these two branches aresecured to the inner wail 2l of the hollow bulkand the cylindrical spaceI2 surrounding the L shell to move forwardly into the compartment I8.Communicated with the compartment I3 is a hollow stationary trunnion 34which encloses the steam line 21. 'I'he trunnion 34 is journalled in acollar 35 iixed to the adjacent end I4 of the casing in opencommunication with the compartment I8. The juncture between the hollowtrunnion 34 and the sleeve 35 is made iiuid tight by a packing gland 36.

Connected to the hollow trunnion 34 is an exhaust pipe 31 which leads-to a steam trap B. The condensate outletv ofthe trap is connected witha waten pump W which constantly draws off the accumulated condensate,and the air outlet of the trap is connected with a vacuum pump V wherebya subpressure is maintained in the hollow trunnion 34 and consequentlyin the chamber I8. Circulation of the heatingk medium through the drierjust as fast as condensation occurs is thus assured and dead`- airspaces are completely precluded.

The condensate is conducted to the hollow trimnion 34 by a trough-likeextension 38 projecting therefrom into thecompartment 4I8 in which thecondensate accumulates, as now about to be described.

Dividing the compartment I8 into two semicircular chambers 39 and 40 aretwo radial Walls 4I and 42. The walls 4I and 42 are in line andterminate short of the center of the unit where each connectsrespectively with two angularly Adisposed walls 43 and 44.

As clearly shown in Figures 2 and 3, the angularly disposed walls 43 and44 substantially surround the trough-like extension 38 of the hollowtrunnion and as the drier revolves. or oscillates back and forth, firstone set of angularly disposed walls and then the other is disposed abovethe open top of the trough 48.

At their inner extremities, the angularly disaccesso posed walls haveelongated openings 45 and turned up flanges 46 so that condensateaccumulating within the chambers 39 and 40 and running down the sides ofthe walls 4I and 42 and over the angularly disposed walls 43 or 44during oscillation of the apparatus, runs through the openings 45 intothe-trough 38.`

Inasmuch as the oscillation of the unit issuicient to carry ilrst oneand then theother set of angularly disposed walls over the open top ofthe trough, the manner in which the chambers 39 and 40 are drained ofcondensate will be readily apparent. i

While the invention thus far described, through the provision of assuredcirculation of the heating medium greatly improves the operation ofdriers in general, it 'has particular application to the vacuum type ofdrier in which the drying compartment is substantially evacuated. Forthis purpose, screened openings throughthe hollow bulkhead l5communicate the interior of the inner shell with the space orcompartment 5i defined by the cup shaped end I6.

The end wall I6 has a nozzle or .nipple 52 fixed thereto to which asuction pipe 53' is attached. To allow for oscillation of the dryingunit and obviate' the necessity for a packed joint between the suctionline and the nozzle or nipple 52, the suction line is in the form of arubber hose, as shown and described in Patent No. 1,561,166.

To aiord access to the compartments i8 vand 5|, the ends I4 and I64 maybe provided with openings having removable covers S3.

Attention is now specically directed to the arrangement of the tubes 23which together with the cylindrical space I2 provide for the circulationof the heating medium. IAs shown in Figures 2 and 3, these tubes arearranged in two sets A and B on opposite sides of a planepassing throughthe unit in linewith the partition walls 4| and 42.

The tubes of each set are arranged in tiers or shelves spaced one abovethe other and inclined `slightly from the center to theoutside when thedrum is in an intermediate position, shown in Figure 2'. 'I'his inclinedarrangement of the tubes facilitates discharging the drier, for when thedrum is in its discharging position with the opening 24' lowermost, thedownward inclination of the shelves will-promote more rapid discharge.

The-tubes comprising each shelf or tier are so located with respect toeach other that when the green material is first deposited into thedrying compartment, it is prevented by its inherent nature from droppingthrough the spaces between the tubes, so that as the drum is oscillatedback and forth, the material is rolledirom one shelf to another andtumbled as it moves, thus continuously turningL the material andinsulting uniform drying.

As the material dries, "it becomes bri and especially in the case ofmalt, it is very undesirable at Vthis stage to throw the material fromone.

'than be tumbled across thehshelves and from one side of the shell `tothe other. In this manner,

the desired turning of the material is effected without the danger ofinjuring the material after -it becomes brittle.-

From the foregoing description taken in connection with the accompanyingdrawings, it will be readily apparent to those skilled in the art towhich this invention appertains, that the con-fl struction of driers formalt, grains, vegetables and. the like has been greatly improvedthereby, particularly through the provision of means for insuringcirculation of the heating medium and through the provision of novelmeans for agitating or turning the material during the drying process.y

What I claim as my invention is:

1. In a drier of`\the character described, a rotatable casing having anend wall, a partition wallwithin-the container spaced `from said endwall to cooperate therewith in defining a closed end compartme t, ahollow partition wall at the opposite end of he rotatable container tocoop,- erate with the first mentioned partition wall in defining amaterial receiving compartment, a plurality of ducts communicating theinterior of the hollow partition wall with the iirst mentionedcompartment, an inlet for heating medium passing through said rstmentioned compartment and through the material receiving compartmentforfcommunication with the hollow partition wall'.

dene a closed chamber, a hollow partition wallv cooperating with thefirst mentioned partition wall and other of the casing walls to dene. amaterial receiving compartment and cooperating with the opposite end ofthe casing to deiine a suction chamber, hollow heat transfer elementsconnecting the rst mentioned partition wall with the inner wall of thehollow partition to communicate said rst mentioned compartment with theinterior of the hollow partition, means for conducting a temperaturemodifying medium into the interior of the hollow partition, means forwithdrawing said medium from the iirst mentioned partition, said hollowpartition having screened openings commiinicating the material receivingcoinpartment with said suction chamber, and means connected with thesuction chamber through which said suction chamber and consequently thematerial receiving compartment may be evacuated. V

3. In a drier of the character described, a rotatable-unit comprising acasing closed at its ends, a partition wall adjacent one closed end ofvthe casing and cooperating with said end to form a closedvgcompartment,a hollow, partition wall adjaceniifthe opposite end of-'the casingcooperating wiiifsaid end to form a suction chamber and cooperating withthe first mentioned partition wall to deiine a material receivingcompartment, said hollow partition wall having screened openingstherethrough for permitting the passage of,

gases from-the material'vreceiving compartment into the suction chamber,means through'which the suction chamber may be evacuated wherebymaterial within the material receiving compartment may be subjected tothe eiect of vacuum, a supply line vfor a heating medium, extendingthrough the first mentioned compartment and the material recei ingcompartment for communication with the nterior of the hollow partitionwall, hollow heat exchanging-elements communicating the interior of thehollow partition wall with said iirst mentioned compartment, and meansfor exhausting spent heating medium from the ilrst mentioned compartmentso that heating medium is caused to circulate through the hollowpartition wall and the hollow heat exchanging elements.

4. In a drier of the character described, a casing mounted foroscillation and having an end wall, a partition within the casingforming one wall of a material receiving compartment and cooperatingwith said end wall to define a closed exhaust compartment, a heatexchanger within the material receiving compartment comprising hollowheat exchanging elements opening to said closed exhaust compartment,means for exhausting spentheating uid from the exhaust compartmentincluding a hollow trunnion extending through said end wall oi' thecasing, and means for withdrawing condensate from said closed exhaustcompartment comprising an open topped trough Vconnected with said hollowtrunnion, and baille walls within'the closed exhaust compartment fordirecting condensate into the open topped trough during oscillation ofthe unit.

5. In a drier including a casing rotatable about a xed axis and havingapartition wall dividing the casing at one end thereof into an 'exhaustcompartment and a materialreceiving compartment, means for circulating aheating fluid through the material receiving compartment includinghollow heat exchanger elements having open ends secured to saidpartition and communicating with the exhaust compartment, a stationeryhollow member having a freely rotatable connection axial to the axis ofrotation of the casing with an outer wall of the exhaust compartment andconnected with the exhaust compartment to provide an exhaust portthrough which spent heating medium is exhausted from said compartment,and meansfor withdrawing 'condensate from said compartment comprising anopen topped trough connected with said hollow member, and baille wallswithin the exhaust compartment for guiding and conducting condensateaccumulating therein into the openv topped trough as the unit turnsabout its axis, of gyration.

6. In a drier, a rotatable drum, partitions in said drum dividing thesame into end compartments and a central material receiving compartment,means i'or communicating one of the end compartments with the materialreceiving compartment so as to allow the extraction of gases from thematerial receiving compartment by suction applied to said endcompartment, means communicated with said end compartment through which.suction may be applied thereto, an inlet for heating medium passingthrough the opposite end compartment and through the material receivingcompartment for connection to the partition at said mst designated endvor th drum, said partition be hollow to receive the -heating medium,hollowv heat exchanging elements passing thrugh the material receivingcompartment for communicating the interior ot the hollow partition withsaid opposite end compartment, and means for exhausting spent heatingmedium from said last named end compart- `ment, said exhausting meansincluding an exhaust pipe connectible with a suction source so as topromote'circulation of the heating medium.

7. In a drier o! the character described, a rotatable \drum, hollow heatexchanging elements disposed longitudinally within said drum, said heatexchanging elements being arranged in two tiers at'vopposite' sides ofan unrestricted space extending substantially diametrically across theinside o! the drum to provide, opposite shelves upon which materialv tobe dried rests to be tumbled and turned by sliding over the shelvesofthe container such material is rolled and turned to present all partsthereof to the heating surfaces provided by said tubes and as thematerial drys it falls through between the tubes to preclude throwingthe material from one side of the container to the other.

9. In a drier, a rotatable drum adapted to contain material to be dried,a heat exchanger unit within the drum comprising a plurality of tubesarranged parallel to the axis 'oi' the drum and disposed in opposed setsof tiers on opposite sides of ya central plane extending longitudinallythrough the drum, said tiers of tubes providing shelves upon which thematerial being dried is supported to be tumbled from one shelf toanother as the drum turns, said drum having a charging and dischargingopening substantially in line with the central plane on opposite sidesof which the sets of tiers are arranged, and said tiers of tatable drumadapted to contain material to be4 dried, a plurality of heat exchangertubes extending longitudinally through the drum, said tubes beingarranged in opposed sets of tiers with the tubes comprisingone setspaced from those comprising the other set to denne a substantialunrestricted spaceextending across the inner ends of the tiers, and withthe individual tubes of each tier arranged in staggered relationship andeach tier comprising at least two rows of tubes spaced apart a distanceless than the diameter of the tubes but suiiicient to allow the materialafter it has been dried a predetermined amount to fall through thetiers.

11. In a drier of the character described, a drum rotatable about a xedaxis, a partition wail within the drum cooperating with an end wallthereof to'pdefine an exhaust compartment and one end of a materialreceiving compartment to contain the material to be dried, a heatexchanger unit within the material receiving compartment, a supply linefor conducting a heating medium to the heat exchangerunit comprising axed section extending through an axial opening in said end wall of thedrum to said partition wall and a movable section rotatable 12. In adrier of the character described, a drum rotatable about a xed axis, apartition wall adjacent one end of the drum to cooperate therewith informing an exhaust compartment and also forming one end wall of amaterial receiving compartment, a heat exchanger unit within thematerial receiving compartment including ducts opening to the exhaustcompartment, a supply line for conducting a heating medium to the heatexchanger unit comprising a xed section passing through an axial openingin said'end wall of the drum and a movable section joined to the xedsection at the partition wall, and an v exhaust line including a hollowmember telescoped over the xed section of the supply line and freelyrotatably joined to said end wall of the drum over the opening thereinso as to have direct communication with the exhaust compartment forexhausting spent heating medium therefrom.

DAVID DALIN.

